Definition of "rath"

There are numerous Danish raths in the parish.

1907, James Woods, Annals of Westmeath, Ancient and Modern

Those with Celtic legendry in their heritage—mainly the Scotch-Irish element of New Hampshire, and their kindred who had settled in Vermont on Governor Wentworth’s colonial grants—linked them vaguely with the malign fairies and “little people” of the bogs and raths, and protected themselves with scraps of incantation handed down through many generations.

1931, H. P. Lovecraft, chapter 1, in The Whisperer in Darkness